Machining apparatus



Sept. 5, 1944.

G. .sTUHLFAUTH MACHINING APPARATUs Original-Filed July 1o, 1940 6 Sheets-Sheet 1 G. STUHLFAUTH' MACHINING APPARATUS sept. 5, 1944.

Original Filed July l0, 1940 lll 5 2 v m m w/N Mm w l a m 7.

6 Sheets-Sheet 2 /A/vm'ro/f 6. 6' TUHL FAU TH 7/ Arron/v Sept. 5, 1944. G. sTUHLFAuTH MACHINING APPARATUS Original Filed July 10, 1940 6 Sheets-Sheet 3 FIG. 7

G. sTuHLFAuTl-l MACHINING API'JARAT'US Sept. 5,A 1944.

original Filed July 1o, 1940 yes sheets-sheet 4 mmm,

G. STUHLFAUTH MACHINING APPARATUS originar Filed July 1o, 1940 Sept. 5, 1944.

GSheets-Sheet 5 lHHHHlh Sept. 5, 1944'. G. sTUHLFAUTH 2,357,616'

MACHINING APPARATUS j Original Filed July 10, 1940 6 Sheets-Sheet 6 v.33a .34a

` STuH/.FAUTH ATTORI/[Y Patented Sept. 5, 1944 2,357,616 MACHINING APPARATUS George Stuhlfauth', Chicago, Ill., assigno' to Western Electric Company, Incorporated, New York, N. Y., a corporation of New York original application July 1o, 1940, serial No". MAJ???`- Divided and this application April 3,v 1942, Serial No. 437,534

11 Claims.

VThis invention relates to a machining apparatus and more particularly to an apparatus for machining partially assembled telephone switch units and is a division of the co-pending application of George Stuhlfauth, Serial No. 344,677, led July 10, 1940.

l In` the manufacture of precision' electrical apparatus, particularly the vertical units adapted for use in automatic telephone exchanges of the cross` bar switching type, various parts of the vertical unit are made up of sub-assemblies and assembled to provide a piece of precision apparatus which is expected to operate for years without failure. The cross bar switch vertical units are assembled on frames which carry cooperatmg parts adapted to be actuated by the vertical unit or control the operation of completing circuits by the vertical unit. It, therefore, becomes essential that the various parts of the apparatus be made with a high degree of precision so that they may be interchangeably assembled. The vertical unit comprises a base member adapted to be mounted on a framework and having lXed thereto an electromagnet, which is formed of a U- shaped pole piece, a core, and a coil Wound about the core. The pole pieces are Welded to the base member and the Core with the coil Wound on it is bolted to the pole pieces -by providing a threaded portion on the extended end of the core, which extends through the base of the U-shaped polepiece. This unitary structure is adapted to have an armature pivoted on an extension of the base and on one of the legs of the pole piece for lactuating switching mechanismwhen theelectromagnet is energized. The base, pole piece, coil and core comprise a sub-assembly for interchangeable assembly with armatures and contact springs to be actuated selectively by the armature. In the manufacture of these sub-assemblies, a number of machining operations are necessary after the various Yparts of the assembly are assembled and plated and it is to the provision of apparatus for performing thesevmachining'v operations that the present invention is directed.

Itis an object of the present 'invention to provide apparatus for automatically performing a 'series of machining opera ions on precision mechanisms and thereby to reduce the cost of such mechanisms and eliminate numerouskmanual operations in the manufacture thereof.

In accordance with one embodiment of the'nvention, a rotary machining apparatus is Yprovided, which includesl a turn tableV automatically indexed step by step about a center spindle to carry a telephone cross` bar. switch vertical' unit to various positions Yin YYtheapparatus; Y where machining operationsV arenperforined upon it. The apparatus includes separatetool drivingmotors vmounted about'the turn table and va main driving motor for driving the turn table andv various of the control earns-,Whichl control l'movements of the various tools in timedA relation to the .indexing of they part being `worked upon. Partsttoy be workedupon are positioned in the machin'eat a loading and unloading station and are then carried bythe ma'cll'ine into associa-V tion with: thef various tools which are mounted as separate within the machine and about the turn table. These tools comprise ve separate units, arranged at iive stations around the turntable, the first of which end-mills one of thelegs of the poley piece of the switch, the second of which performs'- astoning operation `on five separate surfaces`V of the' part lbeing worked upon; that is, it removes, by means of small stones, the excess plating material 4d eiziosit'ed Yat the tipV of the ppl-e pieces and a projecting portion' of the base to'p'rovide'lav sharp: right angle corner on which the armature of the switch'r'nay be pivoted. ThisY station also les off the milling burr Vfrom the legniv the pole piece which was Vend-milled in the previous station'. VThe third unit of the machine receives a part upon indexing of the turn table yand end-mills the'extending end of the magnet core'to cut it slightly under-flush with the fafces'of the pole pieces so that the armature tol be actuatfredk by the electromagnet will alwaysbe spaced from the core of the electromagnet. The fourth station in the apparatus contains a chamfering tool, which is automatically moved upwardly intoA engagement with the core of the magnetto remove the milling burr formed in the preceding station. The part is thenindexed to the iinal operating station, where there'v is` provided: asupply of lacquer which, by means of wicks,k isv applied to the machined surface of the core and the machined surfaceof the pole piece, which was undercut in the first sttaion. After the parts', from which the 4plating hadbeen removed in the machining operations, are thusrecoated, the part is indexed' back'to' the loading and'V unloading station, from which it-may be removed', and a new part is inserted in' place of it. n I

w The present application, which is a division of the' C10-pending application hereinb'efore identied,1is' directed particularly to the portionl of the'v thus brieflyA described apparatus wherein the sto'ning and' filing operations are` performed.

Other related parts of the application, particularly related to the stoning and filing apparatus, will be described and claimed herein.

A better understanding of the invention may be had by reference to the following detailed description, when considered in conjunction with the accompanying drawings, wherein Fig. 1 is a plan view of an apparatus embodying the present invention, part of the cover of the apparatus being broken away to more clearly show the location of the apparatus under the cover;

Fig. 2 is a view in perspective of a cross bar switch vertical unit sub-assembly, including a base member and an electromagnet and its pole pieces, which are to be machined in the apparatus; Y

Fig. 3 is a central sectional View taken substantially on the line 3-3 of Fig. l in the direction of the arrows and showing a section through the loading and unloading station and through the central driving spindle and its associated cams and actuating mechanism;

Fig. 4 is an enlarged fragmentary plan view of the switch-holding fixtures at the loading and unloading station, it bing understood that there are provided six of these fixtures mounted at spaced intervals about the turn table of the apparatus.

Fig. 5 is a sectional view taken substantially along the line 5-5 of Fig. 4 in the direction of the arrows showing some of the details of the xture which clamps the part to be worked upon loosely on the turn table during its passage through the apparatus;

Fig. 6 is aplan view in section, taken substantially along the line 6-6 of Fig. 3 in the direction of the arrows, and shows somewhat in detail the main driving motor and its associated parts, together with the mechanism for intermittently driving the main spindle;

Fig. '1 is a fragmentary vertical sectional view, taken substantially along the line 1-1 of Fig. 6 in the direction of the arrows, and showingin side elevation, some of the parts shown in Fig. 6;

Fig. 8 is an enlarged fragmentary plan View of the second or stoning and ling station of the machine, parts being broken away to more clearly show the details of the apparatus, and, when considered together with Figs. 9, 10 and 11, which are detail vertical sectional views taken through the apparatus along the lines 9-9, |0||l and I, respectively, of Fig. 8, show the mechanism for stoning and iiling the legs of a pole piece and the projecting portion of the base which cooperates with one of the pole pieces to support the armature; and

Fig. 12 is a vertical sectional view taken along the line |2|2 of Fig. 8 in the direction of the arrows showing the stones and le which remove the plating and machining burrs at the filing and stoning station. l

In the drawings, wherein like reference characters designate the same parts throughout the several views, there is shown an apparatus designed to perform machining operations on a cross Vbar switch vertical unit base assembly,

which is illustrated in Fig. 2, and which comprises a main base member 5|, having a central longitudinal embossing 52, which serves to add rigidity to the base structure. Formed integrally with the base, are a pair of bent-over mounting arms 53 and 54, whereby the unit may be mounted on a framework (not shown) after the completion of the assembly oi the various parts 7g of the unit. Welded to the unit at the points 55-55, is a U-shaped pole piece, designated generally by the numeral 56, and having a base portion 51 and extending legs 58 and 59. Nested within the pole piece 56, is a magnet coil 60 wound around a core 6|, which extends through the length of the coil and out through the base portion 51 of the pole piece and holds the coil in place on the pole piece 56. The main base member has formed integrally with it a number of extending lugs, which are not of interest in connection with the present invention, and it ates with the leg 58 of the pole piece to pivotally `support an armature (not shown) on the main base member.

The machine covered by the present invention is designed to prepare the main base member 5| and parts xed thereto, as shown in Fig. 2, for the reception oi the armature (not shown) and is designed to perform various operations on the core 5|, the legs 58 and 59 of the pole piece 56 and on the extending portion 62 of the base. In the apparatus covered by the present invention, at the second operative station of the machine, the surfaces designated 64, 65, 66, 61 and 68 are to be stoned and the edge 69 is to be led to remove the excess plating material from the surfaces 64, 65, 66, 61 and 68 and remove the milling or machining burr from the edge 69. It will be understood that base member 5| and pole piecee 56, after they are welded together, are plated and that the stoning operations remove the excess plating material from the surfaces 64, 65, 66, 61 and 68.

In the description of the apparatus for performing these operations on the verticall unit sub-assembly, the general features of the apparatus will first be described and then the stoning and filing station will be described separately to simplify the description of the machine as much as possible.

Main assembly and loading station The machine, in general, comprises a circular casing 85, as shown most. clearly in Figs. l and 6, which encloses all of the various operating parts of the apparatus. Within the casing are a number of standards 86, 81, 88, 89, 96 and 9| (Fi-g. 6), which extend upwardly from. a subbase 92. The sub-base 92 rests on a circular angle member 93, which may be mounted upon the iloor and xed thereto in any suitable manner. The standards 86 to 9|, inclusive, are of various shapes and their particular construction is immaterial to the present invention, except that they serve to support a main base member 94 and a support plate 95 on which the Various parts of the apparatus are mounted, as will be described in detail hereinafter.

Mounted centrally in the main base member 94, particular reference being had at this time to Figs. 3, 6 and '7, is a main bearing 96, in which there is freely rotatable a sleeve 91. An upper bearing 98 is fixed in the supporting plate 95 and cooperates with the bearing to rotatably support the sleeve 91. Keyed to the sleeve 91 at 99 is a spindle |68, which is rotatable with the sleeve 91, but which may be reciprocated vertically within the sleeve. The spindle |68 has mounted at its upper end a turn table |91, which, upon reciprocation of the spindle, will be elevated and lowered and which, upon rotation of the spindle, will be carried around by the spindle to Carry parts supported by it to the various staelfi sub-base 92, and, through a belt |08", drives a speed reducer (Figs. 6 and' '7); drive shaft extending from' the speed reducer is` designated ||0 and carries a gear which, inzturn, meshes with a gear ||2 mounted on a stud shaft ||3, and carrying a beveled gear ||4 meshing with a beveled gear ||5. The beveled gear ||5 is mounted upon a cam shaft H6, suitably journalled on the sub-base 92, and carrying three cams ||1, ||8 and ||9`. The cam ||1-', as most' clearly shown in. Figs. 3v and '7, has a cam roller bearing against it and supporting a cam arm |2|. The cam arm |2| is pivotally mounted on a b-racket |22 extending downwardly from theV main base member 94'by means of a pin' |23 (Fig. 3). Mounted upon thev cam arm |2r|, directly above the'cam roller |20, is a threaded adjustable abutment |24, which engages a pivot lball- |25 suitably fixed in the lower end of the spindle |00, whereby reciprocatory motion is' imparted to the spindle in a vertical plane to raisetheV turn tab-le |01 cyclically in the operation of themachine. Directly above the gear l, there is mounted', upon the' shaft H0, a grooved cam wheel |30, in the groove of which' there is positionedv a cam roller |3|. Cam roller |3|y is r0- tatably mounted on a cam. lever |32? (Figs. 6 and 7'). Cam lever |32 is pivotally mounted, at |33, on the main base member 94. AnV adjustablelink |34vl interconnects the free end of the cam lever |532 with the pawl arm |05 and imparts oscillatory motion to the pawl; In other words, for each cycle of' the cam wheel |30, the pawl |04 will be. oscillated about the sleeve 91 to step the ratchet |02 one place. Pivotally connected to the paWl arm |05is a link |35, which has pivotally connectedtoit alever |36.. The lever |36'is pivota-lly connected to a bracket |31' mounted onV the main base member 94 by means of a pivot Vpin |38-and carries af loosely mounted brake shoe |39adapted to engage the surface of the ratchet |02 as-the ratchet reaches the end of itsV indexing'movement each time-the ratchet is indexed.

A further extension of theshaft ||0 carries a' chain gear |44 which drives'a chain |45to transmit rotary' motion to a chain gear |46, suitablyV xed to a cam sleeve |41. The'y cam sleeve |41 ismounted for rotation about the sleeveY 91 by means of bearingsl |48 and |49 and has a series of camsv |50, |51|, |52, |53 and |54 fixed t'olit.

Thel cam drives the chamfering unit of the apparatus; the cam |5| drives the milling tool for milling thecore face; the cam |52 drives the apparatus for under-cutting one of the legs of the magnet pole piece; the cam |53 drivesA the cam forstoning the projecting portion of the vertical unit base, the two legs ofl the magnet polev piece, and the apparatus for' ling the intermediate leg of the magnet ypole piece, which has beenundercut; and the cam |54 drivesn the lacquer applying' mechanism. Thevarious piecesA ofV apparatus which these cams drive have been mentioned in a-general way only'and theportion thereof relating to this application will bedescribed-in detail hereinafter.

From-the foregoing, it is believed to be apparent that the spindle |00 may be moved upwardly by The main the. cam I1, and', whilek in any upwardposition, may be rotated. through one-sixth of a revolution by means of apawlv |04 and` ratchet |02. When the turn table mounted on the endr of the spindle |00 is in its lower position, as shown in Fig. 3, a pin |55 (Fig. l) extending upwardly from the upperrsurface of the supporting plate 95 will enter one of.Y a series of bushings |56 set into the turn table |0|' and accurately position the turn table. When the'spindle |'00is raised,-the bushing |56 will be drawn off of the pin |55 and rotary'motion may be imparted through the sleeve 91 and spindle |`00`V to the turn table |0| to carry a piece of apparatus mounted in one of the setsV of nxtures, designated generally by the numeral |51, step b'y step yto the various' machining positions of the apparatus. There` areY six of the sets of fixtures |51 provided about the periphery of the turn table` |0| and are designated generally in Fig. 1 by -the numeral |51, the details of these ix'turesbeing shown in Figs. 3, 4 and 5. As seen in Fig.. 4', the fixture |51 comprises four angle brackets |60, |6`|, |'6`2 andV |63. The brackets |60 andy |6`| serve as bases against which the main'base member 5| of the vertical unit may be pressed by a spring-pressed ball |64 mounted in the angle bracket |62 and engaging against the embossing 52 of the main base' member of the vertical unit. The angle bracket |62 also has mounted in it a spring-pressed plunger |65, which bears against the mounting arm 54 of the vertical unit to draw the innerleg 59 of the pole piece 56 against a` xed stop |56 mounted in the angle bracket |63'. It will be understood that this fixture |51', of which there are six provided, simply serves to loosely hold the vertical unit subassembly during' theV travel of the turntable |`0| to carry' the parts being worked upon to the various operating stations of the apparatus.

The loading and unloading station An operator feding Iparts toand removing them from the apparatus sits at the machine adjacent the'- flattened forward portion thereof, as shown in Fig. l, and after starting the machine in operation through the operation of any suitablel switch to supply electrical current tothe various electrical motors', the turn table will be intermittently indexed andv all of the parts of the apparatus will operate simultaneously to perform operations on a sequence of articles `placed in the fixture |51 by the operator.' unloading station, there is provided means for preventing the operators hands and forearms This mechanism comprisesa hinged gate |15, hinged at |16 to an angle memberv |11. The hinged'gate folds' downwardly to its open position, as shown in dot and dash lines at |18, every time the turn table |0| assumes the position as shown in Figs. 1 and`3. lThe upper half of the hinged gate |15 is set into a round rod |19, which is pivoted at its oppoiite ends in a pair of vertically reciprocable racks |r and |8|. The racks( |8| are slidable in' bearing blocks |82 'and |83, respectively, in which there are positioned gears |84 and |85, respectively, which mesh with their respective racks. The gears |84 and |85 are'interconnected by a' shaft |86. A downwardly extending portion' |81 of the rack 8|vv has fixed to it a push rod |88 (Figs. 3, 6` and 7). The push rod |88 is mounted'on the extending end of a pivoted lever |89, which carriesa cam roller |90. The lever |89 is-pivoted at- 200 to a bracket 20| mounted on the side of standard, and once in each cycleV At the loading andl of the'machine, that is, each indexing of the turn table I9 the push rod |88 will be reciprocated to rotate the gears |84 and |85 first in one direction and then in the opposite direction to movethe gate |15 upwardly and hold it in that position during the indexing of the turn table When the gate is in its lowermost position, the turn table |0| will be stationary and the' various operating mechanisms at the five operating stations will be performing Work on the part being machined. During this interval, an operator may remove a vertical unit sub-assembly from the fixture |51 in front of him at that particular time and may insert another sub-assembly in the fixture |51 so that it may be carried around at the various stations and properly machined. It will be understood that the xture |51 simply holds the vertical unit sub-assembly in yposition by light spring pressure exerted on the spring-pressed pawl |64 and the plunger |65 The turn table |0| rotates in a counter-clockwise direction, as shown in Fig. 1. A sub-assembly mounted in the fixture |51 at the loading and unloading sta-tion will first be carried to the leg milling station, Where an operation not relevant to the present invention will be performed on it, and the turn table |0| will be elevated and indexed one step to carry the sub-assembly, which has thus been machined, to the next operating station, which is the stoning and ling station.

.s'tom'ngr and filing station The mechanism for stoning the surfaces 64, 65, 66, 61 and 68 and for ling the edge 69 of the subassembly being worked upon is most clearly shown in Figs. 8 to 12, inclusive, to which reference will now be had. After the turn table. |0| has been indexed to carry a sub-assembly to the stoning and filing station, the turn table |0| will be lowered to the position as shown in Fig. 3, thereby to carry the sub-assembly base 5| to the position shown in dot and dash lines in Fig. 8. In this position, the sub-assembly will be clamped and held tightly by pneumatic actuated clamping mechanism, the actuating force for which is provided by a pneumatic cylinder 300, which is mounted, by means of brackets 30| and 302, on a vertically extending plate 303, which is suspended from the supporting plate 95, a fragment of which is shown in dot and dash lines in Fig. 11 and which is not shown in Fig. 8, but which is directly above the apparatus as shown in Fig. 8. The plate 303 has a bearing block 304 mounted upon it in which there is journalled a vertically extending shaft 305, which extends upwardly above the level of the supporting plate 95 and has fixed to its end a clamping arm 306. Fixed to the shaft 305 is a lever arm 391 (Fig. 11), in which there is pivotally mounted a yoke 308, adapted to be actuated by a piston rod 309, driven by the cylinder 300, and pinned to the yoke 308 by means of a pin 3|0. The yoke 308 serves also to actuate a link 3| 4which is pivoted on the yoke at 3|2 and connected at its opposite end by means of a pin 3|3 to a lever 3|4, which is, in turn, secured to a rock shaft 3|5. The shaft 3|5 is journalled in a bearing block 320 mounted on the plate 303 and having formed integrally with it an upwardly extending abutment 32| having a surface 322 adapted to be engaged by the rear surface of the legs 58 and 59 of the pole piece 56 when the main base member 5| of the sub-assembly is engaged by the arm 306. The bearing block 320 is also provided with a pair of surfaces 323-323 on which the rear ends of the legs 58 and 59 of the pole piece 56 will rest when the sub-assembly is clamped in this position. The end of the sub-assembly being worked on, which has an extending portion 62 thereon, is clamped against the angle bracket |60, as shown in Fig. 9, by a clamping element 324, which is xed to the shaft 3|5 and engages the sloping surface of the supporting arm 54 of the sub-assembly and forces the base 5| of the sub-assembly against the angle bracket |60.

With a sub-assembly rigidly heldby the clamping assembly just described upon the admission of air to the cylinder 300, the surfaces 64, 65,06, 61 and 68 are stoned by the stoning mechanism and the edge 69 is led by the filing mechanism, as will now be described. Extending downwardly from the supporting plate is a vertically extending plate 325, which is quite similar to plate 303, and, together with the plate 303, provides a bearing in which a rock shaft 326 is oscillatable. Fixed to the left end of the shaft 326 (Fig. 8) is a cam arm 321 carrying a cam roller 328, which engages the cam |53 on the main cam shaft or spindle assembly, as shown in detail in Fig. 3. The shaft 326 also has fixed to it a pair of bell cranks 329 and 330 and the lever 330 is bifurcated to provide two upwardly extending arms 33| and 332. The bell crank 329 has a slot 333 formed in its upwardly extending arm and the arms 33| and 332 have slots 334 and 335 formed in them to receive pins 336, 331 and 338, respectively, which extend outwardly from slide members 339, 340 and 34|, respectively. The slide members 339, 340 and 34| are slidably positioned in slide supports 343, 344 and 345, respectively, which have slots 346, 341 and 348, respectively, through which the pins 336, 331 and 338 extend for engagement by the slotted ends of the bell cranks 329 and 330. The slide support 343 is pivotally mounted on a pivot pin 349 mounted on the vertically extending plate 325 and the slide supports 344 and 345 are pivotally mounted in a bearing 350 being supported by a common pivot pin 35|. Each of the i slide supports 343, 344 and 345 are urged downwardly by coil springsV 356, 351 and 358, respectively, into engagement with stop pins 359, 360 and 36| to normally retain them substantially in the position shown. The slide members 339, 340 and 34| have mounted at their left ends (Figs. 9, 10 and 11) stone supporting clamps 362, 363 and 364, al1 of identical construction, and each having a thumb screw 365 threaded in it for clamping stones 366 in place in the clamps. The underside of each of the slide members 339, 340 and 34| has graduated cam surfaces thereon adapted to ride on cam rollers 361, 368 and 369. Since all of these cams are identical in construction, the one most clearly shown, which is in Fig. 10, will be described in detail and this comprises a sloping surface 310, a flat surface 31|, a sloping surface 312 and a at surface 313. In the operation of the slides, when they are moved to the left by their respective bell crank levers, the sloping surface 3-10 will first engage the cam roller engaged with that particular slide to elevate the slide against the force exerted by the spring 351. Further advancement of the slide to the left will cause the surface 31| to bear against the cam rollers and move the stones carried by the slides under the surfaces 65, 66 and 61. When the sloping cam surfaces 312 engage the roller of its respective slide, the rollers, which are urged upwardly, as will be described, will force the stone against the surface to be stoned under a .predetermined pressure, as will be described more in detail hereinafter. The 'stone will be reciprocated three times while the flat surfaces 3,13 of the vcams are in engagement with their respective cam rollers, thereby to stone the surfaces 65, 6,6 and A61 on the sub-assembly being operated upon. The cam rollers 361, 368 and 369 are mounted ,on ,the free ends of levers 315, 316 and ,311, re-

spectively. These levers are pivotally mounted y.on the vertically extending plates 303 and 325 and are urged to rotate about pivot pins 31,8, v31,9 7and 380 by coil springs 38|, 382 and 383, which are relatively stronger than the coil springs 356,

l35,7 and 358. Y

.It vwill be understood that the contour of the cam |53 (Figs. 3 and 8) is such that in its rotation, it will Vrock the shaft 326 in a counter- .clockwise direction (Figs. 9, 10 and 11;) far enough to carry the stones 366 under their associated portions of the article being worked upon and will then oscillate the shaft 3,26 slightly to .cause the stones 366 to move back overvtheir `corresponding surfaces with which they are in engagement three times and then the shaft 3 26 will be rocked in a clockwise direction sufcient- ,ly to carry similar stones 384 upwardly into yengagement with the surfaces 64 and 68 on the sub-assembly being operated upon and to carry ia le 385 up against the edge 69 to thus stone the surfaces 64 and 68 and removing the milling burr .from the edge 69. The stones 384 are carried in stone supporting clampsY 386 and 3 81 and the file is carried in a le supporting clamp 38,8. The stone supporting clamps 386 and 381 and the le supporting clamp 388 are mounted on the upper ends of slide member 389, 390 and 39|. The slide members 389, 396 and 39| are slidable in slide supports 392, 393, and 394 and are adapted to be actuated by the horizontally extending legs of the bell crank levers 329 and 330. Slide supports 392, 393 and 394 are normally urged to rotate in a clockwise direction about pivot pins 395, 396 and 391 by coil springsV the slide member 340.

From the foregoing, it is believed to be apparent that a sub-assembly carried to the stoning and filing station will be clamped into position in the stoning and filing station by the pneumatically actuated clamps described in detail hereinbefore and that the surfaces 64, 85, 66, 61 and 68 thereof will be stoned at that station and the edge 69 thereof Will be filed to remove the milling burr from it. It will also be understood that each time the turn table |6| isindexed, these operations will be carried on at the stoning and ling station on any sub-assembly which has been carried to that station.

Just prior to the next step of indexing the turn table lill, the air under pressure in the cylinder 390 will be released, thereby to release the clamps Which were holding theY sub-assembly firm at the stoning and filing station, and the turn table will be elevated and indexed to carry the stoned and nled sub-assembly to the next station. In the succeeding stations of the .,apparatus, otherV operations not Apertaining to `the present invention will be vperformed on .the

sub-assembly, being worked upon and the sub- .assembly will be returned to the loading and unloading station, where it may be removed anda new sub-assembly inserted in the xture |51.

Wha-tis claimed is:

' VIn 4an apparatus -ffor .operating upon cross b ar switch vertical uni-ts, a yperiodically indexed turn tablaa fixture on said turn table for receiving a 7part to fbe worked upon, means at one of ,the index v,points or `stations of said-apparatus for squaring -a corner of `said apparatus comprising a ,pai-r of stones normally vpositioned substantially at right angles one to another and in substantially -the same vertical plane, a bell crank lever interconnected -with said stones for imparting reciprocatory motion to the stones to alternately rub-the stoneson .the surfaces to be squared, and

Vcamming vmeans associated with said stones for directing them .into engagement with the surfaes -to ,be stoned.

`2. In an apparatus for operating -upon cross bar switch vertical units, a periodically indexed turn table, a xtu-re on said turntable for receiving va part to be vworked upon, means at oneof the inde-x points :or stations of said apparatus for ,squaring :a lcorner of said apparatus comprising a pai-r of stones normally positioned substantially at right angles one toanother and in substantially the same -vertical plane, a :bell crank lever interconnected with said stones for imparting reciprocatory motionto the stones to alternately rub the stones on-the surfaces to be squared, cam members individual to each of said stones, and a common cam roller associated with both of said cam members for moving the stones into association with the surfaces to be stoned.

3. In an apparatus for operating upon cross bar switch vertical units, a periodically indexed turn table, a xture on said turn table for receiving a part to be worked upon, means at one of the index points or stations of said apparatus for squaring a corner of said apparatus comprising a pair of stones normally positioned substantially at right angles one to another and in sub- 'stantially the same vertical plane, a bell crank lever interconnected with said stones for imparting reciprocatory motion to the stones to alternately rub the stones on the surfaces to be squared, cam members associated with each of said stones, and a resiliently supported cam roller alternately engaged by said cam members to move said stones into engagement with the surfaces to be stoned under a predetermined pressure.

4. In an apparatus for machining articles, a stoning station for squaring a corner of the article, a pivoted bell crank lever, means for oscillating said bell crank lever about its pivot, a pair of slide members mounted for actuation by said bell crank in planes at right angles one to another, a camming member formed integrally with each of said slide members, a grinding member mounted on each of said slide members for grinding angularly disposed surfaces of the article, and a cam roller common to both of said cam members for cooperating with the cam members to urge the grinding members into engagement-with the surfaces to be ground.

5. In a machining apparatus, a corner squaring mechanism including a plurality of vertically reciprocable grinding members, a plurality of horizontally reciprocable grinding members, said vertically and horizontally reciprocable members being arranged in pairs, and a plurality of supports for resiliently supporting the grinding members during their reciprocation, said supports each being common to a vertically reciprocable member and a horizontally reciprocable member.

6. In a machining apparatus, a corner squaring mechanism including a plurality of grinding members arranged in pairs, the members of each pair being reciprocable in planes at right angles one to another, and a resilient support associated with each pair of grinding members to urge the members associated with it into engagement with the surfaces which meet to make the corner.

'7. In a machine apparatus, a corner squaring mechanism including a plurality of grinding members arranged in pairs, the members of each pair being reciprocable in planes at right angles one to another, cam members fixed to said grinding members, and a resiliently vmounted cam roller associated with each pair of grinding members to urge the grinding members into engagement with the surfaces to be ground to form the corner.

8. In a machining apparatus, a nat grinding member, a reciprocable slide for supporting the grinding member, means for reciprocating said slide, a slide supporting element biased to hold the grinding member out of engagement with a surface to be ground, a cam surface formed on the slide, and resilient means for engagement with said cam surface to force the slide supporting element to carry the grinding member into engagement With the surface to be ground.

9. in machining apparatus, a grinding' member, a slidable member for supporting saidv grinding member, a power actuated lever for imparting movement to said slidable member, resilient means normally tending to hold said slidable member in a position to'hold the grinding mem- Vber away from the surface to be ground, a cam surface formed on the slidable member, and a spring pressed cam roller for engaging said cam surface to overcome the resilient means and force the slide Vto move the grinding member against the surface to be ground at a predetermined pressure.

10. A corner squaring apparatus comprising a plurality of reciprocable grinding members arranged in pairs, the members of each pair being reciprocable at right angles one to another to square a corner, a support for resiliently supporting each of said pairs, and an oscillatable lever for actuating both of the members of a pair of members.

11. In a machining apparatus, a corner-squaring mechanism including a plurality of grinding members arranged in pairs, the members of each pair being reciprocable in planes at right angles one to another, a resilient support associated with each pair of grinding members to urge the members associated with it into engagement with the surfaces which meet to make the corner, and

a common actuator for each pair of grinding members comprising an oscillatable lever for imparting reciprocation to the pair of members associated with it.

GEORGE STUHLFAUTH. 

